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Research Vehicle Reaches the Bottom of the Ocean
timothy found BBC coverage of the voyage of the Nereus, which on May 31 dove to the bottom of the Challenger Deep in the Marianas Trench. Only two vehicles have accomplished this feat before, the last 11 years ago. "The unmanned vehicle is remotely operated by pilots aboard a surface ship via a lightweight tether. Its thin, fibre-optic tether to the research vessel Kilo Moana allows the submersible to make deep dives and be highly manoeuvrable. Nereus can also be switched into a free-swimming, autonomous vehicle. ... The Challenger Deep... is the deepest abyss on Earth at 11,000m-deep, more than 2km (1.2 miles) deeper than Mount Everest is high. At that depth, pressures reach 1,100 times those at the surface."
Aye aye, Captain!
Wow, that is great. Hope they find some interesting stuff down there. Maybe some animals we didn't even know existed. Next up: Building the Seaquest
Do they have a good pizza/wing place down there?
Have you fscked your local propeller head today?
I'm impressed with the two guys who did it *manned* in the 60s
from tfa :
In January 1960, Jacques Piccard and Don Walsh made the first and only manned voyage in a Swiss-built bathyscaphe known as the Trieste.
The vessel consisted of a 2m-diameter (6ft) steel sphere containing the crew suspended below a huge 15m-long (50ft) tank of petrol, designed to provide buoyancy.
During the nine-hour mission, the two men spent just 20 minutes on the ocean floor; enough time to measure the depth as 10,916m (35,813 ft).
Invaders must die
Men had balls in the 60s.
How we know is more important than what we know.
Oh yeah? Well, I'm going to be the first man to set foot on the surface of the sun!
submersibles actually manage to stay at the bottom of the trench for extended lengths of time? Short visits can only tell scientists so much about ordinary conditions. A permanent unmaned observation station could record a much larger data sample. Now all that's left to do is develop technologies that can withstand the pressure and power themselves of sulphur-feeding clamlike tube creatures.
#Computers do not appreciate sarcasm
Somebody smarter than myself, please comment on why we need a cable over a distance of 11km? There's a ton of off-the-shelf radio equipment that can easily handle that distance with very high bitrates.
I can imagine two possible problems:
First, the ocean might simply be good at blocking transmissions.
Second, the varying pressures and temperatures might distort a signal to the point where it is unusable. I'm referring to dielectric effects and the fact that the dielectric constant would not be constant in this sort of operation. But would it be "constant-enough"?
It may give us access to 100% of the sea floor, but given the expense of sea exploration, how much will we actually explore? Setting records is nice and all, but it takes time, effort, and money to map the deep sea floor in any kind of detail.
It should be able to take samples and such, but what about repeat dives? The artile was a bit lacking, but hopefully google will turn up the juicy details on this particular little bot....
Men had steel balls in the 60s.
Fixed that for you.
The Trieste is very cool, you can see it in person at the the US Navy Museum which coincidentally is next door to NCIS headquarters.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
I'm impressed with the two guys who did it *manned* in the 60s
from tfa :
In January 1960, Jacques Piccard and Don Walsh made the first and only manned voyage in a Swiss-built bathyscaphe known as the Trieste.
The vessel consisted of a 2m-diameter (6ft) steel sphere containing the crew suspended below a huge 15m-long (50ft) tank of petrol, designed to provide buoyancy.
During the nine-hour mission, the two men spent just 20 minutes on the ocean floor; enough time to measure the depth as 10,916m (35,813 ft).
Yeah, I remember seeing a special on that when I was younger (like 10 years ago), and I still remember it, because it's such an awesome story. I really suggest that if anyone is bored you look this story up, it's really awesome.
The sad thing is that once they hit the bottom, the sand down there was so fine that it threw up a cloud of it that never cleared during the time that they were there, so they didn't get to see much except for what they saw right before they landed!
-Taylor
Worldwide Military budgets: $2100 billion. Worldwide Space Exploration budgets: $38 billion. Really, world? Really?
It's pretty certain that the components are not functionning at 1 atmosphere of pressure. Give or take, the rule of thumb when diving is that the pressure goes up by 1 atmosphere for every 10m of depth. With a depth of 11000m, that's 1100 atmospheres of pressure. That's one of the most reliable methods they use to measure depth, actually.
It's not the outside pressure that causes things to crumple. It's the difference between outside and inside pressures. With that in mind, and keeping in mind that electronics don't get decompression illness, I think it'd make more sense to pressurize the sub. Especially considering that it's a lot easier to contain high pressure at the surface than it is to withstand it at the bottom... case in point, I have an aluminum scuba tank sitting in my basement which is pressurized to 3200 PSI. That's over 217 atmospheres of pressure inside the can, a fifth of the way to the pressure at the bottom of the ocean, and it's not even close to the highest pressure scuba tank I've ever seen. (it's about the max pressure you can have with a yoke connector, but a DIN connector can take a significantly higher pressure).
The bottom line, though, is that you can make a sub that can withstand a *much* greater depth by designing/building it to be pressurized on the inside, too.
If you believe everything you read, you'd better not read. - Japanese proverb
That'll make for one traumatic moment when the lead mermaid tries to surface and bursts open from the tremendous drop in pressure. I don't think my kids would want to see that one.
Uhh. those solid state components you're thinking of tend to have voids in them, e.g. what's under that lid on the CPU.. a bare die and a bunch o' bond wires. Squish city at 1000 Atm.
What about wires? More than enough pressure to push water through the wire using the insulation as a tube.
It is REALLY, REALLY hard to design stuff to work at 1000Atm. What do you use for bouyancy? (Trieste used gasoline.. a liquid that is about the same compressibility as water) Syntactic foam with silica microspheres is fairly popular, because the tiny hollow spheres are pretty strong.
Interestingly, it's harder to design something that won't crush than something that won't explode. That is, building a compressed gas tank to hold 20,000 psi is easier than building one that won't crush under 20,000 psi.
After getting through the corona, that should feel downright refreshing.
Todos mis movimientos están friamente calculados
That's why I'd do it at night.
There's active work going on with underwater radio. It's really tough to do in salt water. But it's not quite impossible. There's considerable interest in making something that can push data through 100 meters of water depth. Oil industry operations would like to talk to their stuff on the ocean floor.
At longer ranges, there's at least one research project which claims that there's a transmission window in seawater between 1MHz and 10MHz. They hope to get data across 1KM. That will be useful if it works.
ELF works; the US and the USSR both have used it in the 70-85 Hz band. The trouble with ELF is that the wavelengths are so long at 80Hz that you need an antenna the size of a county.
Are you sure that's the only time men got down there? I'd not be surprised if the Seaview didn't manage it at least once. After all, that's exactly the type of thing she was built for.
Good, inexpensive web hosting
I worked on an ROV simulation back in the 90's and we needed to keep track of how many times the ROV turned around because twists accumulate in the cable. At some point you may have to sit in place and spin for a bit to undo the twists. Terrible things happen when the tether gets too twisted.
You seem to know a bit about submarines so perhaps you could answer a question that has puzzled me. If you build a submarine like an onion with a hull inside a hull and put pressurized water / air between the two hulls to half the outside pressure would each hull then only need to be strong enough to resist half the external pressure?
I can't see the flaw but it feels wrong because it seems to imply that it would be at least theoretically possible to build a submarine out of sheets of tin-foil as long as there were enough layers and the pressure could be maintained accurately enough.
I used to have a better sig but it broke.
So much for progress.
Depends - Quote:"By mimicking a brick-and-mortar molecular structure found in seashells, University of Michigan researchers created a composite plastic that's as strong as steel but lighter and transparent."
CC.
TaijiQuan (Huang, 5 loosenings)
Didn't the Titanic already make this journey? /Oh, you meant "and returned". //My bad...
I am the unwilling control for my Origin.
That idea won't work because it doesn't actually make sense. While it is definitely an interesting question; and one that I was initially puzzled by, I think you will be surprised by how clumsy the intuitive logic that brings us to that conclusion is. Consider your onion, with two layers, and you are standing between them. To make things simpler, lets assume that instead of water pressure you actually have pressure from weights, and lets also change your onion from spherically shaped shells to just two flat surfaces. For example, you could imagine that you are just standing on an imaginary, levitating sheet of plywood and there is a sheet of plywood above you. The "water pressure" from above you is say 100 lbs. This is how many weights are on the sheet of plywood above you, and it is as much as you can hold. So you say, lets "pressurize" the intermediate onion layer (you), and you position springs on both sides of you (or you could use water pressure). With this new pressurized layer, you can now withstand twice as much "water pressure" from above you, for a total of 200lbs. But that has nothing to do with how much pressure is being exerted on this imaginary sheet of plywood beneath you. As you see, you could build a million onion shells and it wouldn't change anything about how much pressure the inner most layer, or the bottom sheet of plywood, must withstand. Indeed, all submarines already use your multiple hull theory, but not in the way you imagine. They all must withstand the pressure from a layer of ocean above them AND a layer of atmosphere above the ocean--the ocean doesn't protect against the atmospheric pressure.